I created a character mesh using the manuel bastioni, and then wanted to use the rig created by rigify. I followed the steps as in this video: https://www.youtube.com/watch?v=dYiAd_08-0k
When I parent the character mesh to the rig, there are a bunch of vertex groups created. But, when I click on any of them and click "select" in edit mode, no vertices are selected. This also means that the rig is not really skinned - no vertex moves along with the rig. I have looked online for other's having a similar issue, and none of those apply to this case (for e.g., scale transform is applied before parenting).
Here is a google drive to the blend file, saved right after I did the parenting. The metarig is present but hidden, in case you want try regenerating the rigify rig. What is going wrong?
My .blend file can be found Here